Fuel injection system for internal combustion engines

Abstract

A method of lubricating and cleaning a fuel injector of a fuel injection system of an internal combustion engine during running of the engine including delivering both a lubricant and a cleaning additive to the injector. The injector injects directly into the combustion chamber of the engine. The lubricant and cleaning additive are delivered to the fuel exit area of the injector.

The claims defining the invention are as follows: 
     
       1. A method of lubricating and/or cleaning a fuel delivery injector of an internal combustion engine during running of the engine, the injector being part of a dual fluid injection system using a compressed gas to effect injection of a liquid fuel, the liquid fuel being delivered by entrainment by the compressed gas, the method comprising promoting the delivery of at least one of a lubricant and cleaning additive by directly delivering the at least one of the lubricant and cleaning additive to the compressed gas to assure delivery of the lubricant and/or cleaning additive to the injector. 
     
     
       2. A method according to claim 1 wherein the lubricant and the cleaning additive are mixed together prior to delivery to the injector. 
     
     
       3. A method according to claim 1 wherein the cleaning additive is incorporated within the lubricant. 
     
     
       4. A method according to claim 3 wherein at least the cleaning additive is delivered to areas upstream of a fuel exit end of the injector. 
     
     
       5. A method according to claim 1, wherein the dual fluid injection system further comprises a gas capture volume in communication with at least one of a fuel metering injector and a gas delivery injector, wherein at least the cleaning additive is delivered to the gas capture volume. 
     
     
       6. A method according to claim 1 wherein the lubricant and/or cleaning additive is accurately metered in dependence on the engine operating conditions. 
     
     
       7. A method according to claim 1 wherein the internal combustion engine uses a lubricant for general lubrication of the engine and the same lubricant is delivered to the injector. 
     
     
       8. A method according to claim 1 wherein the cleaning additive is an ashless dispersant or detergent. 
     
     
       9. A method according to claim 1 wherein the injector is at least partially constructed from porous material. 
     
     
       10. A method according to claim 9 wherein the injector includes a valve seat made of porous material. 
     
     
       11. A method according to claim 1 wherein the injector is at least partially constructed from self-lubricating metal. 
     
     
       12. A method according to claim 1 wherein the engine is a two stoke engine. 
     
     
       13. A dual fluid injection system for an internal combustion engine comprising at least one fuel delivery injector comprising a valve member and a valve seat, a portion of the valve member being in sealing engagement with the valve seat when the injector is in the closed position, the flow of fuel to the engine being controlled by the sealing and unsealing engagement of the portion of the valve member with the valve seat, the dual fluid injection system further including a compressed gas supply arranged to deliver compressed gas to the fuel delivery injector whereby the compressed gas is used to effect injection of a liquid fuel, the liquid fuel being delivered by entrainment by the compressed gas, and a delivery element which delivers at least one of a lubricant and a cleaning additive directly into the compressed gas such that the lubricant and/or cleaning additive can be subsequently supplied to at least one impact area within the injector. 
     
     
       14. A dual fluid injection system according to claim 13 further comprising a gas capture volume in communication with the injector, and means for delivering at least one of the lubricant and the cleaning additive to the gas capture volume. 
     
     
       15. A direct injection system according to claim 13, wherein the valve member is of the poppet type, the portion of the valve member which sealingly engages the valve seat having an outwardly diverging shape, the valve seat having a surface for cooperating with the shape of the valve member portion to facilitate sealing engagement therebetween. 
     
     
       16. A direct injection system according to claim 74 wherein the valve member portion is hemispherical in shape. 
     
     
       17. A direct injection system according to claim 13, wherein the injector is at least partially constructed from self-lubricating metal. 
     
     
       18. A direct injection system according to claim 13, wherein the injector is at least partially constructed from porous material. 
     
     
       19. A direct injection system according to claim 18, wherein the injector includes a valve seat made of porous material. 
     
     
       20. A direct injection system according to claim 13 wherein the injector injects into a prechamber in communication with a combustion chamber of the engine. 
     
     
       21. A dual fluid injection system of an internal combustion engine comprising: at least one fuel delivery injector having a valve member and a valve seat wherein a portion of the valve member is in sealing engagement with the valve seat when the injector is in the closed position and the flow of fuel to the engine is controlled by the sealing and unsealing engagement of the portion of the valve member with the valve seat,   fuel means for supplying liquid fuel to the fuel delivery injector;   compressed gas means for supplying compressed gas to effect injection of the liquid fuel by entrainment in compressed gas; and   supply means for promoting the delivery of at least one of said lubricant and said cleaning additive by directly supplying the at least one of said lubricant and said cleaning additive to the compressed gas to assure delivery of the lubricant and/or cleaning additive to at least one impact area within the injector.